Certain substituted methylbenzoic acids and substituted methycyclohexane carboxylic acids

ABSTRACT

The invention relates to compounds of the formula

United States .Paten Knowles I Oct. 9, 1973 Eliel CERTAIN SUBSTITUTED METHYLBENZOIC ACIDS AND SUBSTITUTED METHYCYCLOHEXANE CARBOXYLIC ACIDS Inventor: Richard N. Knowles, Hockessin,

Del.

Related U.S. Application Data Division of Ser. No. 635,304, April 20, 1967, which is a continuation-in-part of Ser, Nos. 574,499, Aug. 18, 1966, and Ser. No. 574,276, Aug. 18, 1966.

Assignee:

US. Cl. 260/514 R, 260/514 B, 260/515 R Int. Cl. C07c 61/08, CO7c63/04 Field of Search... 260/514, 515,514 R,

References Cited OTHER PUBLICATIONS et al., J. Org. Chem., Vol. 24, pp. 151-155,

Primary Examiner-Leland A. Sebastia AttorneyHerbert W. Larson 571 ABSTRACT The invention relates to compounds of the formula nscmc 01H,

wherein R is cycloalkyl (C 10 C Cycloalkylalkyl (C to C bicycloalkyl (C to C and tricycloalkyl (C to C and wherein R is alkyl 0 to c cycloalkyl c. to c cycloalkylalkyl (C to C bicycloalkyl (C to C or tricycloalkyl (C to C These compounds are useful as intermediates in preparing N-acylcylclohexyl amines, having utility as animal repellants.

13 Claims, No Drawings CERTAIN SUBSTITUTED METHYLBENZOIC ACIDS AND SUBSTITUTED METHYCYCLOHEXANE CARBOXYLIC ACIDS CROSS-REFERENCE This application is a divisional application of US. Pat. application Ser. No. 635,304, filed April 20, 1967, which in turn is a continuation-in-part of US. Pat. application Ser. No. 574,499, filed Aug. 18, 1966, and Ser. No. 574,276, filed Aug. 18, 1966.

BACKGROUND OF THE INVENTION Application Ser. No. 532,544, filed Mar. 1, 1966 now abandoned and Ser. No. 574,276, filed Aug. 18, I966 relate to compounds containing cyclohexyl ring structures and having utility as animal repellants.

The present application is directed to those compounds useful as intermediates for making the animal repellants described in application Ser. Nos. 532.544 and 574,276.

SUMMARY OF THE INVENTION This invention relates to five classees of intermediates for making N-acylcyclohexylamines.

More specifically, this invention refers to intermediates for synthesizing potent animal inhalation irritant compounds of the formula:

A NCR1 H l S i Rho-V wherein R is hydrogen, methyl or ethyl; R, is hydrogen or alkyl of 1 through 4 carbon atoms;

and

R is striaght chain or branched alkyl of 3 through 8 carbon atoms, cyclobutyl, cyclohexyl, cyclopentyl, cycloheptyl, cyclooctyl, cyclononyl, cycloalkylalkyl of 5 through 10 carbon atoms, bicycloalkyl of 7 through 10 carbon atoms, or tricycloalkyl of 10- through 11 carbon atoms. The intermediate compounds'are described in the following formulas:

H 3 RaC- H wherein R is bicycloalkyl of 7 through 10 carbon toms or tricycloalkyl of 10 through 1 1 carbon atoms.

3 U H II Rr-C-Q-C-Clia wherein R is cycloalkyl of 4 through 9 carbon atoms cycloalkylalkyl of 5 through carbon atoms, bicycloaklyl f 7 through 10 carbon atoms, or tricycloalkyl of 10 through 11 carbon atoms.

R5C COH wherein R is cycloalkyl of 4 through 9 carbon atoms, bicycloalkyl of 7 through 10 carbon atoms, cycloalkylalkyl of 5 through 10 carbon atoms, or tricycloalkyl of 10 through 11 carbon atoms.

0 H H Rz-C s 0-011 "r, V H

wherein R is alkyl of 3 through 8 carbon atoms, cycloalkyl of 4 through 9 carbon atoms, cycloalkylalkyl of 5 through 10 carbon atoms, bicycloalkyl of 7 through 10 carbon atoms or tricycloalkyl of 10 through 1 1 carbon atoms.

H H Rz-C S N-R W H wherein R is hydrogen, methyl or ethyl;

R is alkyl of 3 through 8 carbon atoms, cycloalkyl of 4 through 9 carbon atoms, cycloalkylalkyl of 5 through 10 carbon atoms, bicycloalkyl of 7 through 10 carbon atoms, or tricycloalkyl of 10 through 1 1 carbon atoms,'with thelimitation that the l and 4 groups on the cyclohexyl ring must be in the cis configuration.

PREPARATION The animal repellant compounds are prepared using the intermediates of formulas (2) through (6) and the 30 following synthetic route:

R, R, and R in he following reactions are as defined above in formula (1).

III

i MIRQ cm AIC a pared according to the following reactions where R becomes R during reaction IX.

The Friedel-Crafts reaction (l) is run by carefully adding the acid chloride to a stirring mixture of alumi' num chloride and benzene. A slight molar excess of catalyst is used; benzene serves as both a solvent and reactant. The acid chloride is added at such a rate so as to keep the temperature of the slurry at about 30-40-C. The mixture is stirred for 1 additional hour after all of the acid chloride is added, and then water is slowly added to decompose the catalyst. Sufficient water is added so that all the solids are dissolved. The phenylalkyl ketone is isolated from the benzene solution and is purified by distillation.

The WolffKishner reduction (ll) is run in Z-(Z-ethoxyethoxy )ethanol using a modification of the procedure given by I. Cason, et al. in Organic Synthesis, Collective Vol. IV, John Wiley and Sons, New York, (1963), p. 510. Once the reactans are mixed, they are heated to reflux for a period of 3 to hours. The reflux temperature is generally in the l30-l40 C. range. After completion of the reflux period, the solution is cooled and poured into 3 to 4 volumes of water. The alkylbenzene product is extracted with pentane and purified by distillation.

The F riedel-Crafts reaction (III) is run by mixing approximately equimolar quantities of the. reactants together in hexane or nitromethane at less than 5 C, The

stirring mixture is slowly allowed to warm to room temperature, and when hydrogen chloride evolution subsdies, the mixture is refluxed several hours. Water is then added slowly to decompose the catalyst. A sufficient quantity of water is then addes so that all of the solids are "dissolved. The desired acetophenone deriva- 'tive is isolated from the organic phase, and purified by distillation. Gas-liquid chromatography on an F & M Model 500 Gas Chromatographer using a 2' X O.D.

5 stainless steel column, containing percent Carbowax M on 60-80 mesh Diatoport T indicates that about 90 percent of the acetophenone is the 1,4 isomer and 2 percent is the 1,2 isomer. The l,2 isomer has the shorter retention time.

after, the mixture is heated to reflux, and the distillate collected until the pot temperature reises to 95 -9 7 C.; most of the methanol is distilled. The potis then cooled to room temperature. In those reactions where R has a low molecular weight such as cyclobutyl the sodium benzoate derivative remains dissolved; however, when R becomes larger, such as bicycloheptyl the sodium benzoate derivative precipitates as a soapy solid. Sulfur dioxide is bubbled into the alkaline pot concentrate until the pH drops below 3. The precipitated benzoic acid derivative is either filtered and washed with water,

,30 or extracted with methylene chloride depending on pentane.

The catalytic hydrogenation (V) is performed at two to three atmospheres of hydrogen using platinu oxide as catalyst and glacial acetic acid as solvent. A Parr Hydrogenation Apparatus is suitable for these reactions.

This reaction produces a cis/trans isomer mixture of about 2 or 3/1. The cis and trans designation refers to the relationship of the 4-alky1 su'bstituent and carboxylic acid group on the cyclohexane ring, this is illustrated below cis COJH

I V trans The Schmidt reaction (V1) is performed by dissolving the cyclohexane carboxylic acid derivative in a mixture of chloroform and concentrated sulfuric acid. Sodium 'i 'azide is then added in small portions to the stirring mixture at a rate sufficient to keep the reaction temperature between 35 and 45 C. The mixture is stirred at about 45 to 50C. until the bubbling nearly stops (1 to 3 hours). The mixture is then transferred to a separatory funnel, and the lower, gelatinous-sulfuric acid layer is slowly dripped onto ice. The amine sulfate precipitates as a soapy material which slowly crystallizes. The chloroform should be kept away from theice water mixture since it makes the work-up much more difficult. Those amines which crystallize as the hernisulfates or sulfates are filtered and washed with water. It is convenient to store these amines as their salts. Those amine salts which fail to crystallize are converted to the free bases by making the sulfuric acid solution alkaline, and extracting the aminewith dichloromethane. The amine is then purified by distillation. The Schmidt reaction proceeds without changing the cis/- trans product ratio.

The acylation (VII) can be performed by dissolving the free amine in an equal volume of dimethylacetamide (DMAC) or dimethylformamide (DMF) and adding an excess of the desired acid anhydride to the stirring solution. This reaction is very exothermic. The solution is stirred for ten minutes, and then it is poured into to 100 volumes of water. The amide separates as an oil which subsequently crystallizes.

The acylation (VII) can be performed using the amine sulfate directly according to the following procedure. The amine sulfate is ground into a powder, and added to a 1:1 mixture of DMAC and 20 percent aqueous sodium hydroxide solution; there should be a large excess of base. The mixture is stirred for 10 to b minutes, and then an excess of the desired acid anhydride is added. The mixture warms to about 60 to 65 C. The sulfate entirely dissolves in 10 to minutes. The solution is then pored into 10 to 100 volumes of water. The amide is isolated by the usual procedures given above.

The formamides of reactin VIII are prepared by refluxing the amine with methylformate for several hours.

The excess methylformate is stripped from the reaction, and the residual formamide is purified by recrystallization.

These ayclations proceed without changing the cis/-- the lithium aluminum hydride is destroyed. These amines are purified by distillation.

Reactions X and XI are run according to the procedures described for reactions VII and VIII respectively.

An alternative synthesis route can be used when the appropriately substituted aniline derivatives are available. This route is illustrated below.

The hydrogenation.(XII) can be perfoR ed at l to 3 atmospheres of hydrogen on a Parr Hydrogenation Apparatus using platinum oxide as cataylyst and glacial acetic acid as solvent. Hydrogen up-take is quite slow.

The cis/trans ratio of the cyclohexylamine product is about 1:1.

Reactions XIII and XIV are performed according to reactions VII and VIII discussed above. The cis/transratio for the amides from XII and XIII is about 1:1.

The pure amide isomers from reactions VII, VII, X, XI, XIII and XIV can be separated by chromatography over silicic acid using methylcyclophexane staturated with acetonitrile as the eluting solvent. Isomer mixtures also can be separed by gas-liquid chromatography using can be separated by gas-liquid chromatography using 10 percent Carbowax 20M on -80 mesh Diaoport T. In both of these chromatography methods, the cis isomer elutes before the trans isomer. The cis amine isomer can be regenerated by alkaline hydrolysis of the purifed amide.

The following additional examples describe the inbention in greater detail.

EXAMPLE 1 A 23.9 gram quantity of4-n-butylaniline (from Aldrich Chemical Company) is dissolved in 250 milliliters of glacial acetic acid, and 1 gram of Adams Catalyst (PtO- isadded. The mixture is then hydrogenated at two to three atmospheres using a Parr Hydrogenation Apparatus. To insure complete reduction, the hydrogenation is run over night. The catalyst is then filtered, and the acetic acid is removed under reduced pressure on a steam bath. The concentrate is taken up in ether and washed with dilute, aqueous sodium bicarbonate. The ethereal solution is dried (mGSO filtered and evaporated in vacuum leaving 21 grams of the 4-n-butylcyclohexylamine (n 1.4574). The amine is taken up in two volumes of dimethylcaetamide and treated with one volume of acetic anhydride. The temperature of the stirring solution rises rapidly to 60-80 C. After having stirred for 10 minutes, the solution is poured into ten volumes of water. The oil which separates is extracted with ether. The ethereal solution is dried. (MgSO filtered and stripped leaving an oil which slowly crystallizes. This waxy solid solftens at 57 C. and melts from 79-100 C. Gas-liquid chromatography of this cis/trans mixture of N-acetyl-4-n-butylcyclohexyl-amine on an F & M Model 500 Gas Chromatograph over 10 percent Carbowax 20M on 60-80 mesh Diatoport T in a A" X2 stainless steel column at a temperature of 200 C., a block temperature of 308 for the trans isomer and 1,280 cm for the cis isomer. Anal. Calcd. for C H NO: C, 73.0; H, 11.8; N, 7.1%

Found: C, 72.9; H, 11.7; N, 6,7%

' Mice are treated by aerosol exposure to the cis/trans mixture of N-acety1-4-n-butylcyclohexylamine in the following manner: The compound is administered as an aerosol into 2.8 liter chamber. The exposure chamber consists of a 2.8 liter bell jar over a nebullizer inserted through the follor of the chamber. Mice are exposed for 5 minutes to 200.0 micrograms per liter 1,000Ct). The compound is dissolved in 1.4 ml. of acetone and during a span of 20 seconds the compound is sprayed up into a chamber. No further air is transferred into or out of the chamber during the 5 minute exposure.

After this exposure, irritant effects are observed in all mice exposed. The mice used-as controls exposed to 1.4 ml. of acetone alone exhibit no irritant effects. lrritant effects can be described as the presence of one or more of the following reactive signs:

a. hyperemia of the ears, nose and tail b. abnormal gait, including rubbing of the nose on the floor while running about c. blinking d. slaivation e. depression f. dyspnea g. hunched posuture h. face-pawing.

EXAMPLE 2 A mixture consisting of 400 m1.of benzene and 67 g. (0.5 mole) of aluminum chloride is stirred in a one liter round bottom flash fitted with a stirrer, thermometer condenser connected to a scrubber, dropped funnel, and coolling bath. Cyclobutane carbonyl chloride (50 g.; 0.42 mole) is added dropwise while the pot temperature is held below 35 C, The brown slurry is stirred for 1 hour and then water is cautiously added while the pot temperature is held below 30 C. Sufficient water is added so that all the solids dissolve. Two liquid phases are obtained. The mixture is transferred to a separatory funnel, and the benzene layer is separated. The aqueous layer is washed with 100 m1. of bene'ze which is then combined with the first benzene fraction. The. aqueous solution is discarded. The combined benzene fractions are washed sequentially with 200 ml. of 5 percent aqueous sodium hydroxide solution and 250 ml. of water. The benzene solution is dried with magnesium sulfate, filtered, and evaporated in vacuum. The residual oil is distilled at 67 C. at 0.1 mm.of mercury giving cyclobutylphenylketone (n 1.5455).

Anal. Calcd. for C I-1, C, 82.5; H, 7.6&,

Found: C, 81.9; H, 76.84

EXAMPLES 3 10 I The following phenylketone derivatives are prepared 5. 3-Cyclopentylpropiophenone: B 126 C.; n!)

1.5300 Anal. Calcd. for C H O: C, 83.2; H, 8.9% Found: C, 83.1; H, 8.9%

6. Cycloheptylphenylketone: B 134 136 C.;

7. l-Adamantylphenylketone: m. 495 2 C.

8. 2 -[2.2.2]-Bicyclooctylphenylketone 9. 1-[3.2.l1-Bicyclooctylphenylketone 10. 2-[3.3.11-Bicyclononylphenylketone EXAMPLE 1 1 A solution of potassium hydroxide (140g.; 2.5 mole) in 500 ml. of 2-( 2-ethoxyethoxyl)ethano1 (from Matheson, Coleman & Bell Co.) is prepared by carefully heating the mixture until all of the solids are gone. The olu on- .ccoled..-t9 .heluw .1995. Then 2-[2.2.1]-bicyclopheptylphenylketone (94.7g,; 0.50

. mole) and 99% hydrazine hydrate (110 g.', 2.2 mole) are added all at once. The reactants are refluxed for 4 hours at 135 C., and then the solution is poured into 2.5.1 of water. The oil which separates is extracted wth three-500 ml. portions of pentane. The aqueous phase is discarded, and the combined pentane fractions are dried with magnesium sulfate, filtered and evaporated in vacuu,. The residual oil is distilled at 120 C. at 12 mm. of mercury to give pheny1-2-[2.2.l]-bicyclopheptylmethane (n f 1.5342).

Anal. Calcd. for C H C, 90.3; H, 9.7%

Found: C, 90.8; H, 9.5%

EXAMPLES l2 22 The following phenylmethane derivatives are prepared according to the procedure given for phenyl-2- [2.2.1]-bicyclophptylmethane in Example 8 by substituting the like molar amount of the appropriate phenylketone for 2-[2.2.1 I-bicyclopheptylphenylketone of Example 8. l2. lsobutylbenzene: B 168 C.; n,; 1.5800. 13. Cyclobutylphenylmethane: B 89 C.; 11025 1.5150. 14. Cyclopenthlphenylmethane: 13., 92 C.; m; 1.5 165. 15. 1-cyclopentyl-3-phenylpropane: B 130 C.; [19 1.5090. 8 l6. Cycloheptylphenylmethan: B 1l3 C.; n 1.5218.

Anal. Calcd. for C t-1 C, 89.3; H, 10.7%

Found: C, 88.6; H, 10.4%,

'17. 1Adamantylphenylmethane: B 118- 120 C.;

n 1.5563; m.b 3741 C. Calcd. for C17H22i C. 9Q. 2;H, 9.8%.

Found: C, 89.5; H, 9.5%. 18. 2-[2.2.2]- Bicyclooctylphenylmethane. 19. 1-[3.2.1 ]-Bicycloocty1phenylmethane. 20. 2-[3.3.1]-Bicyclononylphenylmethane. 2 1 1-Homoadamantyphenylmethane. 22. 2-[3.2.0]Bicyclopheptylphenylmethane.

EXAMPLE 23 A solution of cyclobutylphenylmethane (20.5 g=; 0.14 mole) and acetyl chloride (12.5 g.; 0.16 mole) in 400 ml. of hexane is cooled to 0 C. and aluminum chloride (21.5 g.; 0.16 mole) is added all at once. The reaction equipment is similar to that given in Example 2. The stirring mixture is warmed to about 5 C., and held there for 1% hour. The slurry is then warmed to room temperature for 1 hour, and finally refluxed for 30 minutes. Water is then carefully added to decompose the aluminum chloride. Sufficient water is finally added to dissolve all the solids and obtain two liquid phases The mixture is transferred to a seqparoty funnel, and the hexane solution is isolated. The aqueous phase is washed with 100 m1. of hexane, and then discarded. The combined hexane fractions are washed sequentially with 100 ml. of percent aqueous sodium hydroxide solution and 100 ml. of water. The hexane solution is dried with magnesium sulfate, filtered and evaporated in vacuum. The residual oil is distilled at 108 C. at 1 mm. of Hg to give 4' -cyclobutylmethyl-acetophenone (n 1.5388).

Anal. Calcd. for C H O: C, 82.9; H, 8.6%.

Found: C, 83.1; H, 8.5%.

The pertient features in the infra-red spectrum are a very strong peak at 1,680 cm (carbonyl) and a peak at 850 cm indicative of two adjacent benzenoid hydrogens thus showing that the benzene ring has substituents in the 1 and 4 positions.

A gas-liquid chromatogram obtained on an F & M Modeal 500 Gas Chromatograph using a 2' X 541" OD. Stainless Steel column packed with Carbowax 20M on 60-80 mesh Diatoport T with a helium flow rate of 60cc/min. a block temperature of 307 C., an injection port temperature of 262 C., and a column temperature of 225 C. shows that the sample consists of 98% of the 1,4-isomer and 2% of the.1,2-isomer which have retention times of 9.5 and 8.0 minutes respectively.

EXAMPLES 24-42 The following acetophenone derivatives are prepared according to the procedure given for 4' -cyclobutylmethylacetophenone in Example 23 by substituting a like amount of the appropriate alkylphenylmethane derivative for the cyclobutylphenylmethane of Exampe 23. For those compound where R is bi-or tricycloalkyl, nitromethane-can be sued as solvent in place of the hexane. The infra-red spectra for all these compounds are similar to that reported for 4'- eyclobutylmethylacetophenone in Example 23.

24. 4-Isobutylacetophenone: B 1 10C.; n1) 1.51556. 5- nty e qp n n B 22. (24.9 2 51 132- 26. 4'-Cyclopentymethylacetophenone: B 130 132 C.; n0 1.5394.

Calcd for C H O: C, 83.2; H, 8.9%.

Found: C, 83.5; H, 8.9%.

Gas-liquid chromatography under conditions like thosein Example 23 at a column temperature of 200 C. gives peaks at 14.0 minutes (2% of sample) for the 1,2-isomer at 17.5 minutes (98% of sample) for the 1,4-isomer.

2 7. 4-(2-Methylpentyl)acetophenone: B0115 n 1.5120. Anal. Calcd. for C H O: C, 82.3; H, 9.9%.

Found: C, 82.2; h, 9.8%,

Gas-liquid chromatography under conditions like those in Example 23 gives peaks at 6.0 minutes (1% of sample) for the 1,2-isomer and 7.5 minutes (99% of sample) for the 1,4-isomer.

29. 4'-Cyclohexylmethylacetophenone.

30. 4-n-Heptylacetophenone: B, l30l34 C.; m, 1.5084.

31. 4-n-Octylacetophenone: 0.3 128 C. m, 1.5060.

3 2. 4'-(3-Cyclopentylpropyl)acetophenone: 30.5 154 Anal. Calcd. for C H O: C, 83.5; H, 9.6%. Found: C, 83.5; H, 9.6%. 33. 4'-Cycloheptylmethylacetophenone: 13.6.14QC-5 0, 115412.91 Anal. Calcd. for C H O: C, 83.4; H, 9.6%.

Found: C, 83.6; H, 9.7%. 34;.4f-9&19n nxlmetmlasetqphennn 35. 4'-Cyclooctylmethylacetophenone. 36. 4-(2-[2.2. 1 ]-Bicycloheptylmethyl)acetophenone: a -;.90 11125111;...

Anal. Calcd. for C H O: C, 84.2; H, 8.8%. Found: C, 84.1; H, 8.8%. Gas-liquid chromatography under conditions like those given in Example 23 gives a single peak with a retention time of 29.5 minutes. 37. 4-( l-Adamantylmethyl)acetophenone. 38. 4'-(2-[2.2.2]-Bicyclooctylmethyl)acetophenone. 39. 4-( l-[3.2. l ]-Bicyclooctylmethyl)acetophenone. 40. 4-( 2-[ 3.3.1 ]-Bicyclononylmethyl)acetophenone. 41. 4'-( l-Homoadamantylmthyl)acetophenone. 42. 4-(2-[3.2.0]-Bicycloheptylmethyl)acetophenone.

EXAMPLE 43 A solution of 4-cyclobutylmethylacetophenone (20 g.; 0.11 mole) in 225 ml. of methanol is cooled to less than 5 C., and 275 ml. of a 1.29M sodoum hypochlotemperature, and left standing over night. Some chloroform usually separates during the night. The stirring mixture is heated to reflux (80 and distillate 200 ml.) is collected until the pot temperature rises above 95 C. The pot concentrate is cooled to room temperature, and sulfur dioxide is bubbled into it until the pH falls below 3. The precipitate is extracted with two-300 ml. portions of dichloromethane, and the aqueous phase is discarded. The combined dichloromethane solutions are dried with magnesium sulfate, filtered and evaporated in vacuum. The yellow residue is triturated with cold pentane, and filtered. The 4-cyclobutylmethylbenzoic acid melts at 146l49 C. and has an infra-red spectrum showing typical benzoic acid absorption peaks.

Found: C, 75.5; H, 7.6%.

Calcd. neutral equivalent weight:

Found: 198

EXAMPLES 44 62 The following 4-alkylbenzoic acid derivatives are prepared according to the procedure given for 4-cyclobutylmethylbenzoic acid in Example 43 by substituting the appropriate 4-alkylacetophenone in a like molar amount for the 4'- cyclobutylmethylacetophenone of Exampe 43. All of these compounds show the typical benzoic acid absorption peaks in thier infra-red spectra. 44. 4-Isobutylbenzoic acid: m. l43.0144.5 C.

Anal. Calcd. for C11H]4()Z: C, 74.2; H, 7.9%.

Found: C, 74.2; H, 7.9%

45. 4-n-Pentylbenzoic Acid: m. 87.088.5C.

46. 4-Cyclopentylmethylbenzoic acid: m. 143.0-l45 Anal. for (313141502: C, H, 7.9%. Found: C, 76.1; H, 75.%.

47. 4-(2-Methylphentyl)benzoic acid: in. 103-110 C.

Anal. Calcd. for CmHmOzI C, 75.7; H, 8.8%. Found: C, 75.9; H, 8.9%.

48. 4-n-Hexylbenzoic acid. m. 7782 C.

49. 4Cyclohexylmethylbenzoic acid.

50. 4-n-Heptylbenzoic acid: m. 93-96 C.

52. 4-(3-Cyclopenty1propyl)benzoic Anal. Calcd. for C H Q C, 77.5; H, 8.7%. Found: C, 77.6; H, 8.7%.

53. 4-Cycloheptylmethylbenzoic acid: in. 171l73 C.

Anal. Calcd. for C H O C, 77.5; H, 8.7%. Found: C, 77.2; H, 8.7%.

54. 4-Cyclooctylmthylbenzoic acid.

55. 4-Cyclononylmethylbenzoic acid.

56. 4-(2-[2.2.1]-Bicycloheptylmethyl)benzoic acid: in.

Anal. Calcd, for C H Q C, 78.3 H, 7.9%. Found: C, 77.6; H, 7.9%.

Calcd. neutral equivalent weight: 230. Found: 243.

57. 4-( 1-Adamantylmethyl)benzoic acid.

58. 4-(2-[2.2.21Bicyclooctylmethyl)benzoic acid.

59. 4-(l-[3.2.1]-Bicyclooctylmethyl)benzoic acid.

60. 4-( 2-[3.3.1 ]-Bicyclonony1methyl)benzoic acid 61. 4-(1Homoadamantylmethyl)benzoic acid.

62. 4-(2-[3.2.0l-Bicycloheptylmethyl)benzoic acid.

EXAMPLE 63 A sample of 4-cyclobutylmethylbenzoic acid (8.3 g.; 0.044 mole) is dissolved in 250 ml. of glacial acetic acid in a 500 ml. pressure bottle and platinum oxide 1 g.) is added. The mixture is then shaken under a hydrogen pressure of 45 o.s.i.g. on a Parr Hydrogenation Apparatus for 24 hours; the final pressure is 33 p.s.i. g. The catalyst is filtered, and the acetic acid removed in vacuum. The residual oil is taken up in 200 ml. of ether, and washed with two-100 ml. portions of water to remove the residual acetic acid. The ethereal solution is acid: m.

then dried with magnesium sulfate, filterd and evapo- EXAMPLES 64 82 The following 4-alkylcyclohexane carboxylic acid derivatives are prepared according to the procedure given for 4cyclobutylmethylcyclohexane carboiiylic acid in alkylbenzoic acid in a like molar amount for the 4cyclobutylmethylbenzoic acid of Example 63. Infrared spectra of these compounds also show that the henzene rings have been reduced. 64. 4-

12 lsobutylcyclohexane carboxylic acid: B 1 18- 119 C.; n" 1.4638. Calc d. for CUHZQOZI C, H, Found: C, 72.3; H, 11.3%. 65. 4-n-Rentylcyclohexane carboxylic acid: B 138+ C.; n,, 1.4652.

At al- Calsdor rzliaQz C. 7 .-8;H,, l .2 Found: C, 72.8; H, 11.4%. 66. 4Cyclopentylmethylcyclohexane carboxylic acid: 0. 26.11122 -49 0-m- ,3 3.47.

Anal. Calcd. for CmHzgOgI C, 74.2; H, 10.5% Found: C, 73.9; H, 10.7%. 67. 4-(Z-Methylphentyl)cyclophexane carboxylic acid: 80.3 l26130 C.; 119 1.4662.

.AnaLCalcld. for c,,n..o.: C, 73.5;1-1, 11.3%. Found: C, 73.8; H, 11.2%. 68. 4-n-Hexylcyc1ohexane l29l31C.; 111; 1.4666.

Anal. Calcd. for C l -1 0 C,73.4; H, 1 1.4%. Found: C, 74.0; H, 11.1%. 69. 4-Cyclohexylmethylcyclohexane carboxylic acid: m. 62 C. Ca1Cd. for C H O C, H, 10.8%. Found: C, 75.2; H, 10.7%. 70. 4n Heptylcyclohexane carboxylic acid; B 160 C.; n,, 1.4676.

CV, H, l Found: C, 74.5; H, 11.4%. 71. 4-n-Octylcyclohexane carboxylic acid: m. 3639 C. (from acetonitrile) Calcd. for C I-1 0;: C. 75.0;H, 11.4%. Found: C, 75.5; H, 11.9%. 72. 4-(31 Cyclopentylpropyl)cyclohexanecarboxylic acid: B 163 C.; 11925 1.4872.

Anal. Calcd. forC l-l Q z C, 75.5; H, l 1.0%. Found: C, 75.4; H, 10.8%. 73. 4-Cycloheptylmethylcyclohexane carboxylic acid; 30.5 l60162 C.; n 1.4963; m. 4549 C. Calcd 9! C, .511 1.0%-

Found: C, 75.5; H, 10.8%. Neutral Equivalent: Calcd 238. Found 238. 74. 4-n-Nonylcyclohexane carboxylic acid. 75. 4-Cyc1ononylmethylcyclohexane carboxylic acid. 76. 4-(2-[2.2.1]-Bicycloheptylmethyl)cyclohexane carboxylic acid: In. 6473 C. (from ethanol).

Ana. Calcd. for C H O C, 76.2; H, 10.2%. Found: C, 76.1; H, 10.1%. 77. 4-(lAdamantylmethyl)cyclohexane carboxylic acid. 78. 4-(2-[2.2.2]Bicyclooctylmethyl)cyclohexane carcarboxylic acid: B

I boxylic acid.

Example 63 by substituting the appropriate 4- 79. 4-(1-[3.2.l]Bicyclooctylmethyl)cyclohexane carboxylic acid.

80. 4-(2-[3.3.1]-Bicylononylmethyl)cyclohexane carboxylic acid.

81. 4-(1Homoadamantylmethyl)cyclohexane carboxylic acid.

82. 4-(2-[3.2.1]Bicyloheptylmethyl)cyclohexane carboxylic acid.

EXAMPLE 83 A sample f 4-n-hexylcyclohexane carboxylic acid (24 g.; 0.11 mole) is taken up in a mixture of 200 ml. of chloroform and m1. of concentrated sulfuric acid in a 500 ml. Erlenmery flask. Sodium azide (9.8 g.; 0.1 5 mole) is carefully added with a spatual at a rate to keep the temperature of the stirring mixture between 35 and 45 C. After completion of the sodium azide addition, the stirring mixture is heated at 4550 C. for 2 hours; the rate of gas evolution is very slow at this time. The mixture is transferred to a separating funnel and the lower, gelatinous sulfuric acid layer is slowly dripped into one liter of crushed ice. The 4-n-hexylcyclohexylamine hemisulfate crystallizes slowly. The salt is filtered and washed with water; it is almost completely insoluble in water. The melting point is above 300 C.

Anal. Cald'd. for C H- N'l/2H SO C, 62.1; H, 11.3; N, 6.0; S, 6.9%.

The infra-red spectrum shows absorptions characteristic of amine salts and sulfates and has no absorption corresponding to a carboxyl function.

EXAMPLES 84 102 The following 4-alkylcyclohexylamine derivaties or their salts are prepared according to the procedure given for 4-n-hexylcyclohexylamine hemi-sulfate in Example 83 by substituting the appropriate 4- alkylcyclohexane carboxylic acid in like amount by weight for the 4-hexylcyclohexane carboxylic acid of Example 83. In those instances where the freeamines are prepared, the amine salt is dissolved in aqueous sodium hydroxide solution, and the free amine is extracted with dichloromethane. The dichloromethane solution is dried with magneius sulfate, filtered and evaporated in vacuum. The residual oil is distilled in vacuum through a spinning band column. The infra-red spectra of these compounds all show the loss of the carbonyl function and the presence of an amino function. 84. 4-lsobutylcyclohexylamine: B 56C.; n 1.4552.

Anal. Calcd. for C H N: C, 77.4; H, 13.6; N, 9.0;

Found: C, 77.6; H, 13.5; N, 9.1%.

85. 4-n-Pentylcyclohexylamine: B1,, 76 C.; 1.4612. 9

Anal. Calcs. for C H N: C, 78.0; H, 13.7; N, 8.3%.

F01lH ;H, 8.6 86. 4-Cyc1opentylmethylcyclohexylamine hemi-sulfate: m 300 C.

Anal. Calcd. for C, H N'1/2H SO C, 62.6; H, 10.5; N, 6.1%.

Found: C, 62.0; H, 10.7; N, 6.0%.

87. 4-(2-Methy1pentyl)cyclohexylamine: B B, 80-

81C.; nn,. 1.4625. I 4 Anal. Calcd. for C, H ,,N: C, 78.7; H, 13.7; N, 7.6%.

Found: C, 78.3; H, 13.7; N, 8.1%.

88. 4-Cyclobutylmethylcyclohexylamine.

89. 4-cis-Cyclohexylmethylcyclohexylamine sulfate: m. 300 C.

Anal. Calc'd. for C, H N*1/2H SO C, 64.0; H, 10.8; S, 6.6%.

Found: C, 63.9; H, 10.6; S, 6.9%.

90. 4-n-Heptylcyclohexylamine hemi-sulfate hemihydrate: m. 300 C. I

Anal. Calcd. for C H N'l/2H SO -1/2H O: C, 62.3;- H, 11.5; N, 5.6%

Found: C, 62.6; H, 12.0; N, 5.0%.

91. 4-n-Octylcyclochexylamine hemi-sulfate hemihydrate.

Anal. Calc'd. for C H N'l/2H SO 'l/2H O: C, 62.4; H, 11.6; N, 5.2%.

Found: C, 61.8; H, 12.0; N, 5.1%.

hemi- 92. 4-(3-Cyclopentylpropyl)cyclohyexylamine sulfate;

Anal. Calcd. for C H N-H SO C, 54.6; H, 9.5; N, 4.6; S, 10.4%.

Found: c, 55.2; H, 9.8; N, 4.5; s. 9.9%. 93. 4-Cycloheptylmethylcyclohexylamine hemi-sulfate: m 300 C. 94. 4-Cyclooctylmethylcylcohexylamine hemi-sulfate: m 300 C. 95. 4-Cyclononylmethylcylcohexylamine hemi-sulfate: m 300 C. 96. 4-( 2-[2.2. l ]-Bicycloheptylmethyl)cyclohexylamine hemi-sulfate dihydrate: m. 300 C. Calcd for C,.,H N-C, H N1/2H SO., 2H O: C, 57.9; H, 9.6; N, 4.8%

Found: C, 58.5; H, 9.3; N, 4.7%. 97. 4-( 1-Adamantylmethyl)cyclohexlamine m. 300 C. 98. 4-(2-[2.2.2]-Bicyclooctylmethyl)cyclohexy/amine sulfate: m. 300 C. 99. 4-( 1-[3.2.1 ]-Bicycloocty1methy1)cyclohexylamine sulfate: in. 300 C. 100. 4-(2-[3.3.l -Bicyclonony1methyl)cyclohexylamine hemi-sulfate: m.X300 C. 101. 4-( 1Homoadamantylmethyl)cyclohexylamine suflafte: m. 300 C. 102. 4-(2-[3.2.0]-Bicycloheptylmethyl)cyclohexylamine hemi-sulfate: m. 300

EXAMPLE 103 A sample of 4-n-hexylcyc1ohexylamine hemi-sulfate (10 g.; 0.043 mole) is stirred for 10 minutes in a mixture consisting of 100 ml. of dimethylacetamide and 25 ml. of 20% aqueous sodium hydroxide solution. Acetic anhydride (20 ml.) is added with stirring; the temperature rises to -80 C. After the temperature has dropped to about 60 C., the milky suspension is filtered to remove any traces of unreacted 4-n-hexylcyclohexylamine hemi-sulfate. The milky filtrate is poured into 1,200 m1. of water, and the oil which separates crystallizes. Teh crystalline N-acetyl-4-n-hexylcyclohexylamine is filtered and washed with water. It melts from 49 to 87 C.

Anal. Calcd. for C H NO: C, 74.8; N, 12.1; N, 6.2%.

Found: C, 74.7; H, 12.0;N, 6.3%.

Gas-liquid chromatography on an F & M Model 500 Gas Chromatograph using a 2 X r"O.D. stainless steel column packed with 10% Carbowax 20M on 60-80 mesh Diatoport T at a column temperature of 200 C., a block temperature of 308 C. an injection port temperature of 265 C. and a helium flow rate of 60 cc/min. shows that the sample consists of two compounds present to the extent of 64% and 36% which have retention times of 53.3 and 61.8 minutes respectively.

A nuclear magnetic resonance spectrum of the mixture shows that the larger' component is N-acetyl-cis- 4-n-hexylcyclohexy1amine and the smaller The pure isomers are isolated by adsorption chromatography over silicicacid using methylcyclohexane saturated with acetonitrile as the eluting solvent; the adsorbant to compound ratio is 50:1. N-Acetyl-cis-4-nhexylcyclohexylamine melts at 550 to 570 C., and N-acety1-trans-4-n-hyxylcyclohexylamine melts at 1.23.0124 C.

sulfate:

The cis/trans mixtures are used for the purposes of this invention without separation of the isomers.

N-Acetyl-4-n-hexylcyclohexylamines are used. to treat mice according to the procedures given in Example l with like results. As the time mice are treated in such manner with the pure isomers, the cis isomer is shown to be much more of an irritant than the trans isomer.

Examples 104 125 The following N-acyl-4-alkylcyclohexylamines are prepared according to the procedure given for N- acetyl-4-n-hexyleyelohexylamine in Example 103 by substituting in a like molar amount te appropriate 4-alkylcyclohexylamine and acid anhydride for the 4-n-hexylcyclohexy1amine and acetic anhydride of Example 103. 104. N-Acetyl-4-isobutylcyclohexylaminez m. 961 18 C. cis/trans ratio= 63(41.0 min.)/37 (47.2 min.) by G.L.C. method like that in Example 103 at a column temperature of 180 C.

Anal. Calcd. for C H NO; C, 73.0; H, 11.7; N, 7.1%.

Found: C, 73.1; H, 12,2; N, 7.0%

105. N-Butyryl-4-isobutylcyclohexylamine.

106. N-Acety1-4-n-pentylcyclohexylamine: m. 4595C. cis/trans ratio 68(34.3min.)/32(39.9min.) by G.L.C. method like that in Example 103 at a column temperature of 200 C.

Calcd. for C H NO; C, 75.0; H, 11.9; N, 6.6%. Found: C, 73.6; H, 12.3; N, 6.6%. N-Propiony1-4-n-pentylcyclohexylamine. N-Acety1-4-cyclopentylmethylcyclohexylamine: m. 65-78 C. cis/trans ratio 74(33min.)/26(37min.) by G.L.C. Method like that in Example 103 at a column temperature of 225 C.

Calcd. for C H NO: C, 75.4; H, 11.2; N, 6.2%.

.Found: C, 75.2; H, 11.4; N, 6.2%. N-Propionyl-4-cycl0pentylmethylcyclohexylamine. N-Acety1-4-( Z-methylpentyl)cyclohexylamine: m. 5869 C. cis/trans ratio= 87(54.5min.)/13(62.6min.) by G.L.C. method similar to that in Example 103 at a column temperature of 190 C.

Calcd. for C H NO; C, 74.7; 1-1, 12.1; N, 6.2%.

Found: C, 74.6; H, 11.9; N, 6.0%. N-Acety1-4-Cyc1obuty1methylcyclohexy/amine: m. 42-59 C. cix/trans ratio 7843.5min)/22(49.6min) by a G.L.C. Method like that in Example 103 at a column temperature of 200 C.

Found: C, 74,7; H, 11.1; N, 6.5%

1 12. N-Acetyl-4-n-heptylcyclohexylamine; m. 61-114 C.,' cis/trans ratio 64(23.5min.)36(27.0- min) by a G.L.C. method like tjat om Example 103 at a col. temperature of 230 C.

Calcd. for C, H NO: C, 75.3; H, 12.2; N, 5.9%

Found: C, 75.0; H, 12.1; N, 5.9%,

113. N-Acety1-4-n-octylcyclohexylamine; m. 62-82 C. cis/trans ratio 75(31.5min.)25(36.5min.) by a G.L.C. method similar to that of Example 112.

Calcd. for C H NO: C, 76.0; H, 12.3; N, 5.5%.

Found: C, 75.8; H, 12.3; N, 5.4%.

1 l7. N-Acetyl-4-cyclooctylmethylcyclohexylamine.

1 l8. N-Acetyl-4-cyclonoylmethylcyclohexylamine.

1 19. N-Acetyl-4-( 2-[2.2. 1 ]-bicyclohepthylmethy1)cyclohexylamine: m. 1 1 1-l 13 C. cix/trans ratio: 32

73(55.8min.)/27(63.5min.) by G.L.C. method like that in Example 103 at a column temperature of 225 C. Calc'd. for C H NO: C, 77.2; H, 10.9; N, 5.6%.

Found: C, 76.9; H, 10.7; N, 5.6%.

120. N-Acetyl-4-( 1 -adamantylmethyl )eyclohexylamine. 121,. N-acety1-4-(2-[ 2.2.2. ]-bicyclooctylmethy1)cyclohexylamine.

122. N-acety1-4-(2-[3.2.1 ]-bicyclooctylmethyl )cyclohexylamine.

123.N-Acetyl-4-(2-[3.3.1 ]-bicyc1ononylmethy1)cyclohexylamine.

124. N-Acetyl-4-( 1-homoadamantylmethyl)cyclohexylamine.

125. -N-Acety1-4-( 2-[ 3.2.0]-bicycloheptylmethyl)cyclohexylamine.

Example 126 A sample of 4-cyclobutylmethylcyclohexylamine 10 g.; 0.060 mole) is refluxed for 3 hours with 20 m1. of methylformate. The solution is then evaporated in vacuum and the residual N-formyl-4-cyclobutylmethylcyclohexylamine is purified by recrystallizaton from hexane. This N-formyl-4-cyc1obutylmethylcyclohexylamine is used to treat mice and other animals according to the procedures given in United States Pat. application Ser. No. 532,544, filed Mar. 1,1966, now abandoned Example 127 A mixture of N-formyl -4-cyclohexylmethylcyclohexylam ine (b 7-.9g.; 0.035 mole) and lithium aluminum Examples 128-141 The following dialkylamines are prepared according to the procedure described for N-MethyI-N- cyclohexylmethyl-cyclohexylamine in Example 127 by substituting in like amount by weight the appropriate N-formal or N-acetyl-4-alkylcyclohexylamine for the N-formy1-N-cyc1ohexylmethyl-cyclohexylamine in Example 127.

128. N-Methyl-N-(4-cyclobutylmethylcyclohexyl)amine. i

129. N-Ethyl-N.-(4-n-butylcyclohexyl)amine.

130. N-Methyl-N-(4-n-hexylcyclohexyl)amine.

13 1.. N-Ethyl-N-(4-cyclononylmethylcyclohexyl)amine.

1 32. N-Methyl-n-[4-( 3-cyclopentylpropyl)cyclohexyllamine.

133. N-Ethyl-N [4-( 212.2. 1 ]-bicycloheptylmethyl)cyclohexyll-amine.

'1 34. N-Methyl-N-(4-n-heptycyclohexyl)amine.

135. mine. 136. N-Methyl-N-(4-cycloheptylmethylcyclohexyl)amine.

1 37. N-Ethy1-N-[4-(2-methylpentyl)cyclohexyl]amine.

N-Methy1-N-(4-cyc1opentylmethylcyclohexyl )abicyclononylmethyl)cyclohexyHamine. 139. N-Methyl N-[4-( l-adamantylmethyl)cyclohexyl- ]amne.

140. N-Ethyl-n-[4-( 1-adamantylmethyl)cyclohexyl]amine.

141 N-Methyl-N-( 4-[ l-homoadamantylmethyl]cyclohexyl)amine.

EXAMPLES 142 156 The following N-acyl-N-methyl or ethyl-N-4-alkylcyclohexylamine derivatives are prepared according to the directions given for preparing N-acetyl-4-n-hexylcyclohexyamine in Example 103 or N-formyl-4- cyclobutylmethylcyclohexylamine in Example 126 by substituting the obvious reactants in like molar amount by weight for those given in Examples 103 and 126.

142. N-Acetyl-N-methyl-N-(4-cyclobutylmethylcyclohexyl)amine. 143. N-Acety1-N-ethy1-N-(4-n-butylcyclohexyl)amine.

144. N-Formyl-N-methyl-N-(4-n-hexylcyc1ohexyl)amine. 145. N-Formyl-N-ethyl-N-(4-cyc1opentylmethy1cyclohexyl)amine. 146. N-Propionyl-N-methyl-N-(4-cycloheptylmethylcychexy1)-amine. v 147. N-Butanoyl-N-methyl-N-(4-cyc1onony1methylcyclohexyl)amine.

148. N-Acetyl-N-ethyl-N-(4-n-pentylcyclohexyl )amine.

149. N-Acetyl-N-methyl-N-( 4-n-heptylcyclohexy1)amine. 150. N-Acetyl-NQethyl-N-[4-( 2- methylpentyl)cyclohexyl]amine.

151. N-Butanoyl-N-methyl-N-(4-isobutylcyclohexylamine. 152. N-Formyl-N-ethyl-N-(4-n-octy1cyc1ohexyl)amine. 153. N-Formyl-N-methyl-n-[4-(2-[2.2.1]- b o 9. 9mp m thidlzcyqlqhsxy lat i s.

154. N-Acety1-N-ethy1-N-[4-( l-adamantylmethyl)cyclohexyl]-amine.

155. N-Acetyl-N-methyl-N-[4-( l/ -homoadamantylmethyl)cyclohexy1]-amine. 156.

N-Acety1-N-methy1-N-[4(2-[3.3.1]-

bicyclononylmethyD-cyc1ohexyl]amine.

I claim: 1. Acompound of the formula:

wherein pl R is selected from the group consisting of cycloalkyl of 4 through 9 carbon atoms, cycloalkylalkyl of 5 through 10 carbon atoms, bicycloalkyl of 7through 10 carbon atoms, and tricycloalkyl of 10 through 11 carbon atoms.

2. A compound of the formula:

wherein R is alkyl of 3 through 8 carbon atoms, cycloalkyl of 4 through 9 carbon atoms, cycloalkylalkyl of 5through 10 carbon atoms, bicycloalkyl of 7 through 10 carbon atoms and tricycloalkyl of 10 through 11 carbon atoms.

3. A compound according to claim 1 which is 4-cyclobutylmethylbenzoic acid.

4. A compound according to claim 1 which is 4-cyclopentylmethylbenzoic acid.

5. A compound according to claim 1 which is 4-cyclohexylmethylbenzoic acid.

6. A compound according to claim 1 which is 4-(2- [2.2.1 ]-bicycloheptylmethyl)benzoic acid.

7. A compound according to claim 1 which is 4-( l adamantylmethyhbenzoic acid.

8. A compound according to claim 2 which is 4-cyclobutylmethylcyclohexane carboxylic acid.

9. A compound according to claim 2 which is 4- cyclopentylmethylcyclohexane carboxylic acid.

10. A compound according to claim 2 which is 4-cyclohexy1methylcyclohexane carboxylic acid.

11. A compound according to claim 2 which is (2-. [2.2.1 ]-bicycloheptylmethyl)cyclohexane carboxylic acid.

12. A compound according to claim 2 which is 4-(1- adamantylmethyl)cyclohexane carboxylic acid.

13. A compound according to claim 2 which is 4-hexylcyclohexane carboxylic acid. 

2. A compound of the formula:
 3. A compound according to claim 1 which is 4-cyclobutylmethylbenzoic acid.
 4. A compound according to claim 1 which is 4-cyclopentylmethylbenzoic acid.
 5. A compound according to claim 1 which is 4-cyclohexylmethylbenzoic acid.
 6. A compound according to claim 1 which is 4-(2-(2.2.1)-bicycloheptylmethyl)benzoic acid.
 7. A compound according to claim 1 which is 4-(1-adamantylmethyl)benzoic acid.
 8. A compound according to claim 2 which is 4-cyclobutylmethylcyclohexane carboxylic acid.
 9. A compound according to claim 2 which is 4-cyclopentylmethylcyclohexane carboxylic acid.
 10. A compound according to claim 2 which is 4-cyclohexylmethylcyclohexane carboxylic acid.
 11. A compound according to claim 2 which is (2-(2.2.1)-bicycloheptylmethyl)cyclohexane carboxylic acid.
 12. A compound according to claim 2 which is 4-(1-adamantylmethyl)cyclohexane carboxylic acid.
 13. A compound according to claim 2 which is 4-n-hexylcyclohexane carboxylic acid. 